Dissecting the virulence-related functionality and cellular transcription mechanism of a conserved hypothetical protein in Xanthomonas oryzae pv. oryzae
Dissecting the virulence-related functionality and cellular transcription mechanism of a conserved hypothetical protein in Xanthomonas oryzae pv. oryzae
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剖析米黄单胞菌 pv 中保守假设蛋白的毒力相关功能和细胞转录机制。
DOI：
10.1111/mpp.12664
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发表时间：
2018-08-01
影响因子：
4.9
通讯作者：
Liu, Fengquan
中科院分区：
文献类型：
--
作者：
Wang, Bo;Wu, Guichun;Liu, Fengquan
没有明确功能的假设蛋白质主要分布在所有已测序的细菌基因组中。了解它们的强大功能是对细菌学家的基本要求。米黄单胞菌 pv. oryzae (Xoo) 是水稻白叶枯病的病原体，是分子植物病理学研究的模型系统之一。该细菌基因组中四分之一的蛋白质被定义为假设蛋白质，但它们在 Xoo 致病性中的作用尚不清楚。在这里，我们对从菌株 PXO99(A) 中选出的六种假设蛋白进行了框内删除，并发现其中一种蛋白 (PXO_03177) 是该菌株完全毒力所必需的。 PXO_03177 在黄单胞菌中是保守的，预计包含两个与多糖合成相关的结构域。然而，我们发现该基因的突变并不影响细胞外多糖（EPS）和脂多糖（LPS）的产生或修饰，这两种是Xoo产生的与其感染相关的主要多糖。有趣的是，我们发现 PXO_03177 失活显着损害生物膜形成和对十二烷基硫酸钠 (SDS) 的耐受性，这两者被认为在水稻叶片 Xoo 感染过程中发挥关键作用。因此，这些发现使我们能够定义 PXO_03177 在 Xoo 毒力中的函数。此外，我们还发现全局调节因子 Clp 通过直接结合 PXO_03177 的启动子区域来控制 PXO_03177 的转录，为调节该假设蛋白基因的表达提供了第一个细胞调节途径。我们的结果为黄单胞菌中的 PXO_03177 同系物提供了参考信息。
Hypothetical proteins without defined functions are largely distributed in all sequenced bacterial genomes. Understanding their potent functionalities is a basic demand for bacteriologists. Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial leaf blight of rice, is one of the model systems for the study of molecular plant pathology. One-quarter of proteins in the genome of this bacterium are defined as hypothetical proteins, but their roles in Xoo pathogenicity are unknown. Here, we generated in-frame deletions for six hypothetical proteins selected from strain PXO99(A) and found that one of them (PXO_03177) is required for the full virulence of this strain. PXO_03177 is conserved in Xanthomonas, and is predicted to contain two domains relating to polysaccharide synthesis. However, we found that mutation of this gene did not affect the production or modification of extracellular polysaccharides (EPSs) and lipopolysaccharides (LPSs), two major polysaccharides produced by Xoo relating to its infection. Interestingly, we found that inactivation of PXO_03177 significantly impaired biofilm formation and tolerance to sodium dodecyl sulfate (SDS), both of which are considered to play key roles during Xoo infection in rice leaves. These findings thus enable us to define a function for PXO_03177 in the virulence of Xoo. Furthermore, we also found that the global regulator Clp controls the transcription of PXO_03177 by direct binding to its promoter region, presenting the first cellular regulatory pathway for the modulation of expression of this hypothetical protein gene. Our results provide reference information for PXO_03177 homologues in Xanthomonas.